The present invention relates to electric connectors for connecting connection objects.
There is an electric connector that transmits a single data signal as a differential signal using two signal lines, or in other words, an electric connector used for connecting signal circuits of a differential-signal-transmission type. Two types of transmission for digital signals are known, which are an unbalanced type (i.e. a single-ended type) and a balanced type (i.e. a differential type).
In unbalanced-type (single-ended type) signal transmission, a digital signal is determined to be high or low based on a potential difference between a ground line and a single signal line. On the other hand, in balanced-type (differential type) signal transmission, a digital signal is determined to be high or low based on a potential difference between two signal lines. In the latter case, the magnitude of the signal voltage between the two signal lines is the same, whereas the phase between the two signal lines is different by 180°. Furthermore, in transition minimized differential signaling, or TMDS, data transmission is achieved by using two signal lines and a single ground line.
In the balanced-type (differential-type) signal transmission, the impedance matching between positive-signal contacts and ground contacts and between negative-signal contacts and ground contacts must be evenly attained.
In the balanced-type (differential-type) signal transmission, since a noise generated in the two signal lines is cancelled at the input stage of a receiver, the signal transmission can be achieved with higher reliability in comparison to the unbalanced-type (single-ended type) signal transmission.
A known connector for differential signal transmission includes contacts and an insulator supporting the contacts. When using such a connector for transmitting a differential signal, each pair of signal contacts S is connected to a corresponding pair of signal lines, and each ground contact G is connected to a corresponding ground line.
The contacts include a plurality of signal contacts S, a plurality of ground contacts G, and a plurality of general (low-speed) contacts D. The signal contacts S, the ground contacts G, and the general contacts D are arranged in the following order: S, S, G, S, S, G, S, S, D, D, D. An example of such a connector is disclosed in Japanese Unexamined Patent Application Publication (JP-A) No. 2002-334738.
Furthermore, an intermediate connector is also known, which includes a connection member and a housing that houses the connection member. The housing has a jack portion and a plug portion. The connection member has a first contact segment, a second contact segment, and a coupling segment. The first contact segment is substantially U-shaped so that the first contact segment is engageable to a connection terminal of a modular plug. The second contact segment is connectable to an input-output connector. An example of such an intermediate connector is disclosed in Japanese Unexamined Patent Application Publication (JP-A) No. 2000-182733.
In the connector according to Japanese Unexamined Patent Application Publication (JP-A) No. 2002-334748, however, the contacts are combined simply by arranging each pair of signal contacts S adjacent to each other and disposing each ground contact G adjacent to the pair.
For this reason, in a case where the signal contacts S of each pair are switched with each other, the electrical relationship between the pair of signal contacts S and the ground contact G cannot be maintained. Accordingly, when a differential signal is to be transmitted, a high performance cannot be maintained with respect to high-frequency characteristics.
On the other hand, the connection member of the intermediate connector disclosed in Japanese Unexamined Patent Application Publication (JP-A) No. 2000-182733 is not used in view of high-frequency characteristics.